From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- include/uapi/misc/uacce/hisi_qm.h | 40 +++++++++++++++++++++++++++++++++++++++ include/uapi/misc/uacce/uacce.h | 38 +++++++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+) create mode 100644 include/uapi/misc/uacce/hisi_qm.h create mode 100644 include/uapi/misc/uacce/uacce.h (limited to 'include/uapi/misc/uacce') diff --git a/include/uapi/misc/uacce/hisi_qm.h b/include/uapi/misc/uacce/hisi_qm.h new file mode 100644 index 000000000..10504b48e --- /dev/null +++ b/include/uapi/misc/uacce/hisi_qm.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +#ifndef _UAPI_HISI_QM_H +#define _UAPI_HISI_QM_H + +#include + +/** + * struct hisi_qp_ctx - User data for hisi qp. + * @id: qp_index return to user space + * @qc_type: Accelerator algorithm type + */ +struct hisi_qp_ctx { + __u16 id; + __u16 qc_type; +}; + +/** + * struct hisi_qp_info - User data for hisi qp. + * @sqe_size: Submission queue element size + * @sq_depth: The number of sqe + * @cq_depth: The number of cqe + * @reserved: Reserved data + */ +struct hisi_qp_info { + __u32 sqe_size; + __u16 sq_depth; + __u16 cq_depth; + __u64 reserved; +}; + +#define HISI_QM_API_VER_BASE "hisi_qm_v1" +#define HISI_QM_API_VER2_BASE "hisi_qm_v2" +#define HISI_QM_API_VER3_BASE "hisi_qm_v3" +#define HISI_QM_API_VER5_BASE "hisi_qm_v5" + +/* UACCE_CMD_QM_SET_QP_CTX: Set qp algorithm type */ +#define UACCE_CMD_QM_SET_QP_CTX _IOWR('H', 10, struct hisi_qp_ctx) +/* UACCE_CMD_QM_SET_QP_INFO: Set qp depth and BD size */ +#define UACCE_CMD_QM_SET_QP_INFO _IOWR('H', 11, struct hisi_qp_info) +#endif diff --git a/include/uapi/misc/uacce/uacce.h b/include/uapi/misc/uacce/uacce.h new file mode 100644 index 000000000..cc7185678 --- /dev/null +++ b/include/uapi/misc/uacce/uacce.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +#ifndef _UAPIUUACCE_H +#define _UAPIUUACCE_H + +#include +#include + +/* + * UACCE_CMD_START_Q: Start queue + */ +#define UACCE_CMD_START_Q _IO('W', 0) + +/* + * UACCE_CMD_PUT_Q: + * User actively stop queue and free queue resource immediately + * Optimization method since close fd may delay + */ +#define UACCE_CMD_PUT_Q _IO('W', 1) + +/* + * UACCE Device flags: + * UACCE_DEV_SVA: Shared Virtual Addresses + * Support PASID + * Support device page faults (PCI PRI or SMMU Stall) + */ +#define UACCE_DEV_SVA BIT(0) + +/** + * enum uacce_qfrt: queue file region type + * @UACCE_QFRT_MMIO: device mmio region + * @UACCE_QFRT_DUS: device user share region + */ +enum uacce_qfrt { + UACCE_QFRT_MMIO = 0, + UACCE_QFRT_DUS = 1, +}; + +#endif -- cgit v1.3.1